Lesions to the mediodorsal thalamus, but not orbitofrontal cortex, enhance volatility beliefs linked to paranoia.

Beliefs-attitudes toward some state of the environment-guide action selection and should be robust to variability but sensitive to meaningful change. Beliefs about volatility (expectation of change) are associated with paranoia in humans, but the brain regions responsible for volatility beliefs remain unknown. The orbitofrontal cortex (OFC) is central to adaptive behavior, whereas the magnocellular mediodorsal thalamus (MDmc) is essential for arbitrating between perceptions and action policies.

Contextual and Temporal Constraints for Attentional Capture: Commentary on Theeuwes' 2023 Review "The Attentional Capture Debate: When Can We Avoid Salient Distractors and when Not?".

Salient distractors demand our attention. Their salience, derived from intensity, relative contrast or learned relevance, captures our limited information capacity. This is typically an adaptive response as salient stimuli may require an immediate change in behaviour.

Local and global reward learning in the lateral frontal cortex show differential development during human adolescence.

Reward-guided choice is fundamental for adaptive behaviour and depends on several component processes supported by prefrontal cortex. Here, across three studies, we show that two such component processes, linking reward to specific choices and estimating the global reward state, develop during human adolescence and are linked to the lateral portions of the prefrontal cortex. These processes reflect the assignment of rewards contingently to local choices, or noncontingently, to choices that make up the global reward history.

Oxygen and the Spark of Human Brain Evolution: Complex Interactions of Metabolism and Cortical Expansion across Development and Evolution.

Scientific theories on the functioning and dysfunction of the human brain require an understanding of its development-before and after birth and through maturation to adulthood-and its evolution. Here we bring together several accounts of human brain evolution by focusing on the central role of oxygen and brain metabolism. We argue that evolutionary expansion of human transmodal association cortices exceeded the capacity of oxygen delivery by the vascular system, which led these brain tissues to rely on nonoxidative glycolysis for additional energy supply.

10 Simple Rules for a Supportive Lab Environment.

The transition to principal investigator (PI), or lab leader, can be challenging, partially due to the need to fulfil new managerial and leadership responsibilities. One key aspect of this role, which is often not explicitly discussed, is creating a supportive lab environment. Here, we present ten simple rules to guide the new PI in the development of their own positive and thriving lab atmosphere.

Characterization of structural and functional network organization after focal prefrontal lesions in humans in proof of principle study.

Lesion research classically maps behavioral effects of focal damage to the directly injured brain region. However, such damage can also have distant effects that can be assessed with modern imaging methods. Furthermore, the combination and comparison of imaging methods in a lesion model may shed light on the biological basis of structural and functional networks in the healthy brain.

Ten simple rules to study distractor suppression.

Distractor suppression refers to the ability to filter out distracting and task-irrelevant information. Distractor suppression is essential for survival and considered a key aspect of selective attention. Despite the recent and rapidly evolving literature on distractor suppression, we still know little about how the brain suppresses distracting information.

Attentional Control in Subclinical Anxiety and Depression: Depression Symptoms Are Associated With Deficits in Target Facilitation, Not Distractor Inhibition.

Mood and anxiety disorders are associated with deficits in attentional control involving emotive and non-emotive stimuli. Current theories focus on impaired attentional inhibition of distracting stimuli in producing these deficits. However, standard attention tasks struggle to separate distractor inhibition from target facilitation.

Behavioral flexibility is associated with changes in structure and function distributed across a frontal cortical network in macaques.

One of the most influential accounts of central orbitofrontal cortex-that it mediates behavioral flexibility-has been challenged by the finding that discrimination reversal in macaques, the classic test of behavioral flexibility, is unaffected when lesions are made by excitotoxin injection rather than aspiration. This suggests that the critical brain circuit mediating behavioral flexibility in reversal tasks lies beyond the central orbitofrontal cortex. To determine its identity, a group of nine macaques were taught discrimination reversal learning tasks, and its impact on gray matter was measured.

Selective inhibition of distracting input.

We review a series of studies exploring distractor suppression. It is often assumed that preparatory distractor suppression is controlled via top-down mechanisms of attention akin to those that prepare brain areas for target enhancement. Here, we consider two alternative mechanisms: secondary inhibition and expectation suppression within a predictive coding framework.

Contrasting Effects of Medial and Lateral Orbitofrontal Cortex Lesions on Credit Assignment and Decision-Making in Humans.

The orbitofrontal cortex is critical for goal-directed behavior. Recent work in macaques has suggested the lateral orbitofrontal cortex (lOFC) is relatively more concerned with assignment of credit for rewards to particular choices during value-guided learning, whereas the medial orbitofrontal cortex (often referred to as ventromedial prefrontal cortex in humans; vmPFC/mOFC) is involved in constraining the decision to the relevant options. We examined whether people with damage restricted to subregions of prefrontal cortex showed the patterns of impairment observed in prior investigations of the effects of lesions to homologous regions in macaques.

Distinct Mechanisms for Distractor Suppression and Target Facilitation.

Unlabelled: It is well established that preparatory attention improves processing of task-relevant stimuli. Although it is often more important to ignore task-irrelevant stimuli, comparatively little is known about preparatory attentional mechanisms for inhibiting expected distractions. Here, we establish that distractor inhibition is not under the same top-down control as target facilitation.

The extreme capsule fiber complex in humans and macaque monkeys: a comparative diffusion MRI tractography study.

We compared the course and cortical projections of white matter fibers passing through the extreme capsule in humans and macaques. Previous comparisons of this tract have suggested a uniquely human posterior projection, but these studies have always employed different techniques in the different species. Here we used the same technique, diffusion MRI, in both species to avoid attributing differences in techniques to differences in species.

Contrasting Roles for Orbitofrontal Cortex and Amygdala in Credit Assignment and Learning in Macaques.

Recent studies have challenged the view that orbitofrontal cortex (OFC) and amygdala mediate flexible reward-guided behavior. We trained macaques to perform an object discrimination reversal task during fMRI sessions and identified a lateral OFC (lOFC) region in which activity predicted adaptive win-stay/lose-shift behavior. Amygdala and lOFC activity was more strongly coupled on lose-shift trials.

Testing the inter-hemispheric competition account of visual extinction with combined TMS/fMRI.

Theoretical models of visual neglect and extinction entail claims about the normal functioning of attention and parietal cortex in the healthy brain: (1) 'pseudoneglect', a commonly observed attentional bias towards left space, reflects the greater dominance of parietal cortex activity of the right versus left hemisphere; (2) the capacity to distribute attention bilaterally depends causally on the relative balance of parietal activity between the hemispheres; (3) disruption of the dominant right parietal cortex shifts this inter-hemispheric balance leftward, causing a rightward shift in attentional bias. We tested these claims using low-frequency offline transcranial magnetic stimulation (TMS) to transiently inhibit activity in the right angular gyrus/intra-parietal sulcus, followed by a visual detection task to assess changes in attentional bias, and functional magnetic resonance imaging (fMRI) to test for the predicted leftward shift in brain activity. The task required participants to covertly monitor both hemifields to detect and report the location of upcoming transient visual targets that appeared on the left, right or bilaterally.

A neural circuit covarying with social hierarchy in macaques.

Despite widespread interest in social dominance, little is known of its neural correlates in primates. We hypothesized that social status in primates might be related to individual variation in subcortical brain regions implicated in other aspects of social and emotional behavior in other mammals. To examine this possibility we used magnetic resonance imaging (MRI), which affords the taking of quantitative measurements noninvasively, both of brain structure and of brain function, across many regions simultaneously.

Causal effect of disconnection lesions on interhemispheric functional connectivity in rhesus monkeys.

In the absence of external stimuli or task demands, correlations in spontaneous brain activity (functional connectivity) reflect patterns of anatomical connectivity. Hence, resting-state functional connectivity has been used as a proxy measure for structural connectivity and as a biomarker for brain changes in disease. To relate changes in functional connectivity to physiological changes in the brain, it is important to understand how correlations in functional connectivity depend on the physical integrity of brain tissue.

The organization of dorsal frontal cortex in humans and macaques.

The human dorsal frontal cortex has been associated with the most sophisticated aspects of cognition, including those that are thought to be especially refined in humans. Here we used diffusion-weighted magnetic resonance imaging (DW-MRI) and functional MRI (fMRI) in humans and macaques to infer and compare the organization of dorsal frontal cortex in the two species. Using DW-MRI tractography-based parcellation, we identified 10 dorsal frontal regions lying between the human inferior frontal sulcus and cingulate cortex.

On the relationship between the "default mode network" and the "social brain".

The default mode network (DMN) of the brain consists of areas that are typically more active during rest than during active task performance. Recently however, this network has been shown to be activated by certain types of tasks. Social cognition, particularly higher-order tasks such as attributing mental states to others, has been suggested to activate a network of areas at least partly overlapping with the DMN.

Giving credit where credit is due: orbitofrontal cortex and valuation in an uncertain world.

The orbitofrontal cortex (OFC) has long been implicated in aspects of learning and adaptive decision making in changeable environments, but its precise role has remained elusive. One potential reason is that anatomical and functional distinctions within the OFC have often been overlooked. Here, we review findings centered largely on recent lesion studies in macaque monkeys from our laboratories that have investigated the causal role of the lateral and medial parts of the OFC (LOFC and MOFC) in choice behavior in uncertain, multioption environments.

Frontal cortex and reward-guided learning and decision-making.

Reward-guided decision-making and learning depends on distributed neural circuits with many components. Here we focus on recent evidence that suggests four frontal lobe regions make distinct contributions to reward-guided learning and decision-making: the lateral orbitofrontal cortex, the ventromedial prefrontal cortex and adjacent medial orbitofrontal cortex, anterior cingulate cortex, and the anterior lateral prefrontal cortex. We attempt to identify common themes in experiments with human participants and with animal models, which suggest roles that the areas play in learning about reward associations, selecting reward goals, choosing actions to obtain reward, and monitoring the potential value of switching to alternative courses of action.

Diffusion-weighted imaging tractography-based parcellation of the human parietal cortex and comparison with human and macaque resting-state functional connectivity.

Despite the prominence of parietal activity in human neuroimaging investigations of sensorimotor and cognitive processes, there remains uncertainty about basic aspects of parietal cortical anatomical organization. Descriptions of human parietal cortex draw heavily on anatomical schemes developed in other primate species, but the validity of such comparisons has been questioned by claims that there are fundamental differences between the parietal cortex in humans and other primates. A scheme is presented for parcellation of human lateral parietal cortex into component regions on the basis of anatomical connectivity and the functional interactions of the resulting clusters with other brain regions.

Assessment of unilateral spatial neglect: scoring star cancellation performance from video recordings--method, reliability, benefits, and normative data.

Unilateral spatial neglect, a debilitating condition affecting awareness of one side of space, is commonly assessed using cancellation tasks in which patients cross out targets distributed over a sheet. Standard scores emphasize the left-right distribution of omissions. Here, the additional value of extracting temporal as well as spatial aspects of performance from video recordings was examined.